| Tahmid |
I am making a new SMPS inverter, 300W. I need help with the transformer winding. And I also want to know what frequency is ideal if I am using an ETD39 or ECR40 type ferrite core.
Which IR MOSFET is best for use over here? (I am asking for IR MOSFETs because we can not find MOSFETs from other manufacturers in Bangladesh.) |
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| guitar_joe |
etd39 and ecr40 are standard sizes for cores. Operating frequency depends on the material of the core.
Give some basic specs for the mosfets you need and use a parametric search IR's website. |
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| areza |
| where do u get these cores?? |
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| golam |
etd and ecr cores are special type E cores produced for high frequency smps use. If you use etd 39/ecr40 core, you can get 250 watt if frequency is 25 kHz, 350 watt if frequency is 50 kHz and 450 watt with 100 kHz. Very useful ha!!
I made 250 watt high frequency inverter with ecr 40 core and my turns were as follows:
Primary-- -- 3-0-3
Secondary-- 73
My frequency was 25 KHZ .
One should be very careful while making ferrite core transformer. It is better to be Primary to be set first. |
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| golam |
| regarding mosfet. I used irfp 054 which is of 60 volts and 250 watt and its resistance of drain to source during on is 14 mili ohm. It is to 247 type. It is very sturdy and reliable and useful for high frequency use. |
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| Tahmid |
Actually I am a student of class VIII. I cannot buy the parts myself all the time.
Last February, I went to New Delhi with my father to see the electronics fair in Pragati Maidan. There I found different companies producing Ferrite Core. One of the companies, Hinoloy, presented me 3 ETD39 and 3 ECR40 cores and the engineer told me that these cores are useful for high frequency inverter. From then on, I am doing test and trial with these cores.
I produced one high frequency inverter for 200W capability but it gets hot after fifteen minutes or so and cannot withstand more than 20W for longer duration. Once I tried with 200W bulb and it could take the load for fifteen minutes, but after that all the parts became hot and could not take the load. Probably my configuration regarding frequency, turn, driver and MOSFETs require detailed modification. I require help from everyone for that reason.
PLEASE HELP ME IN THIS REGARD. |
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| areza |
maybe you r too early for this kind of electronics involve lethal voltage would kill u or injure u seriously, obviously its not a beginner kind of think, safety is must,
for ips u really need two stage inverter , first one 12v dc to 22v dc , second one 220v dc to 220v ac , if u want to use inductive load like fan , |
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| areza |
| u can make the transformer as golam mentioned , make sure the frequency is ~25khz to ~30khz and not less then 23khz or u would go into core saturation when temperature of the core rises, it seems u already having this problem after 15 min of 200 watt load, for now u can use irfz44 or irf3205 or whatever u have in ur hand, just put each set of mosfet on separate heatsink, use tight layout with minimum ground loop for mosfet to gate driver, so the mosfet will work properly and dont get hot and start to smoke, |
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| Tahmid |
For the last two years, I have been deeply associated with electronics. I have been trained intensively by my father and have undergone different courses. I have already constructed a 300 Watt Linear IPS which I am using in my room.
Linear system is inefficient and bulky transformer is required, which is a real nuisance. That's why I am moving onto SMPS. For the last six months I have tested different SMPS circuits and am now quite confident that I can tackle such complex circuits. I have read different books on SMPS written by renowned power electronics writers.
Obviously, this is all going alongside my studies and schoolwork. Power electronics is my hobby. I have a complete laboratory in my house. I hope, with the guidance of you all, I can make my circuits effective and successful. |
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| Tahmid |
Where comes the matter of core saturation, I do not see how that would occur, because my oscillator is running at 30kHz.
But probably, some error in my circuit is causing heating. (This is my view.)
Anyway, I am constructing a new control circuit and transformer according to the details given by golam.
Special thanks to golam for the transformer details and areza also for the explanation. |
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| golam |
don't bother for core saturation. ETD/ECr core can withstand upto 300 KHZ. Make sure that sg3525 circuit is constructed for high frequency as most of the circuits in internet is for 50 HZ. Make the Battery voltage as clean as possible with adequate filtering. Provide snubber circuit for controlling ringing and provide Zener diode for each mosfet(gate to source/ground) and that should be 18 volt if your Battery power is 12 volt. After converting AC 220 v, use high frequency diodes for dc conversion and use inductor and also adequate capacitors for filtering and use more numbers to offset ESR problem of the capacitors. Your dc to dc conversion is complete. If you want to go further and want to use in your house as ips, convert the dc voltage to ac by full bridge circuit.
I will give you some tips regarding full bridge circuit to convert dc 220v to 220v ac for use in your home next time. Not so difficult ha ha ha!!
Be careful regarding capacitors with lethal high voltage. If you are testing in open circuit, please discharge the capacitors after each test.
Be careful again from the high voltage charged capacitors. Otherwise it will be easier for you to go to God. Not fun- ha ha ha!!! |
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| golam |
If you want to make full bridge circuit for converting 220v dc to 220v ac,you should use mosfets with min. 500v capacity. you can use 4 nos. of irfp 460. Since 2 mosfets will be of high side and 2 in low side, you should use mosfet drivers with high side(with floating ground) and low side capability. So, you can use 1 sg3525 and 2 ir2110 drivers. Use proper output inductor and decoupling capacitors. Your 220v ips is ready for use. Very easy-ha ha!!
If you use open circuit for testing, discharge the charged capacitors before putting hand on any parts on the circuit. |
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| luka |
| quote: | Originally posted by golam
etd and ecr cores are special type E cores produced for high frequency smps use. If you use etd 39/ecr40 core, you can get 250 watt if frequency is 25 kHz, 350 watt if frequency is 50 kHz and 450 watt with 100 kHz. Very useful ha!!
I made 250 watt high frequency inverter with ecr 40 core and my turns were as follows:
Primary-- -- 3-0-3
Secondary-- 73
My frequency was 25 KHZ .
One should be very careful while making ferrite core transformer. It is better to be Primary to be set first. |
250w is right, but at 48k you get 467w, 935w at 96k...
100kHz is high freq... |
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| luka |
| quote: | Originally posted by golam
If you want to make full bridge circuit for converting 220v dc to 220v ac,you should use mosfets with min. 500v capacity. you can use 4 nos. of irfp 460. Since 2 mosfets will be of high side and 2 in low side, you should use mosfet drivers with high side(with floating ground) and low side capability. So, you can use 1 sg3525 and 2 ir2110 drivers. Use proper output inductor and decoupling capacitors. Your 220v ips is ready for use. Very easy-ha ha!!
If you use open circuit for testing, discharge the charged capacitors before putting hand on any parts on the circuit. |
Or you could use trafo to drive all 4 fets... + if you use 220v and chop and invert it you will get voltage that would be same as 155vAc...235vAc that I have here has peak of 330v, so you should think what would be better for inverter to put out: 220v peak or more... |
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| areza |
golam, i m sure u talking about pure sine wave inverter , if so then I have to mention that u need 310v dc to produce 220v ac which is in RMS value ,
There are many things one have to look at when designing a class d style dc to ac inverter, not so easy though , specially transient voltage , filter design , cross conduction , switching loss on high voltage, and many more.
dont get confuse , core saturation is not related to frequency rather it related to voltage and time, |
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| areza |
| hi luka , i m looking for a trafo gate driver which can work 0-100% duty cycle, like driving a class d amp for music , can u help me with this, thanks in advance |
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| Tahmid |
| I am getting a lot of help from luka and golam. And I request you two to continue providing me guidance and advice. |
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| Tahmid |
| quote: | Posted by luka
Or you could use trafo to drive all 4 fets... + if you use 220v and chop and invert it you will get voltage that would be same as 155vAc...235vAc that I have here has peak of 330v, so you should think what would be better for inverter to put out: 220v peak or more... |
Luka, is it not easier, less troublesome and more convenient to use dedicated gate driver ICs instead of using transformer for gate driving.
ICs have in-built system of making floating ground for high side MOSFET driving. But if we use transformer, should we use three separate transformers or three separate windings for ensuring floating ground for high side MOSFET driving.
It is easier to use ICs like IR2110 instead of the troublesome transformer. Is that not true? |
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| golam |
| quote: | Posted by luka
250w is right, but at 48k you get 467w, 935w at 96k... |
I have got the information from Tauscher Co. of Germany which produce good quality cores. I have collected some of their etd/ecr cores from China and used for my inverters. I used them for making 250 watt capacity ips. Those information from Tauscher Co. may be for continuous duty and for using 2/4 hours for ips, I think more wattage can be produced as duty cycle is less.
I tried to make 600 watt with those core with 80 KHZ but it becomes very hot and I am reverted back to 250/300 wattage.
For safe use over 500 watt, one require to use ETD-44 core- according to the Company. |
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| golam |
| quote: | Posted by luka.
Or you could use trafo to drive all 4 fets... + if you use 220v and chop and invert it you will get voltage that would be same as 155vAc...235vAc that I have here has peak of 330v, so you should think what would be better for inverter to put out: 220v peak or more... |
If transformer is used for driving 4 mosfets, for high side 2 mosfets, 2 separate windings required for ensuring no short circuiting and 1 winding for 2 low side. Transformer can be used with the criteria I have mentioned or Mosfets will be destroyed immediately with boom !! 3 separate transformers required or one transformer with 3 output windings required for separate floating grounds for 2 high side mosfets and 1 for 2 low side mosfets.
Instead of using transformer, one can use 1 sg3525 and 2 drivers as I mentioned. Choice is different. One can choose according to preference. |
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| golam |
For Areza,
I am talking about square wave inverter. For square wave, rms value and peak value is same. So no need to convert to 310 volts. Since sg3535 is having adjustment capability through feedback from the output, no need for worrying for load variation.
For modified sine wave to run inductive load, one require to add dead time in between two phases for creating difference between rms and peak value and in this case(for modified sine wave) you require to convert 310v dc to 220v ac. And of course for sine wave inverter, you require to convert 12v dc (or any value dc) to 310 or more volt dc and then convert that high volt dc to 220 v sine wave ac through full bridge circuit without any transformer.
For using square wave ips for inductive load, one requires to use both resistive and inductive load. Then there will not be any problem. |
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| golam |
For Tahmid,
I tried with transformer for full bridge and faced lot of problem as the gate driving signals through transformer is not as efficient as gate driving dedicated ics. You can try but if you ask me, I will advocate to use dedicated gate driving ics. |
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| luka |
| quote: | Originally posted by areza
hi luka , i m looking for a trafo gate driver which can work 0-100% duty cycle, like driving a class d amp for music , can u help me with this, thanks in advance |
I think it can't be done, even with IR you would have to have better, by that I diffrent supply then normaly, to have 100% D.C.
Well trafo won't work this way anyway, since trafos can't transfer DC from primary to secondary (100% D.C.) |
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| cerrem |
For that type of core you want to stay under 300mT for your max Flux density...when operating bewteen 100kHz to 200kHz range...
Also...with Forward converter make sure to use a reset winding or a resonant reset....this way you must start at origin for each cycle...
CHris |
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| luka |
| quote: | Originally posted by Tahmid
Luka, is it not easier, less troublesome and more convenient to use dedicated gate driver ICs instead of using transformer for gate driving.
ICs have in-built system of making floating ground for high side MOSFET driving. But if we use transformer, should we use three separate transformers or three separate windings for ensuring floating ground for high side MOSFET driving.
It is easier to use ICs like IR2110 instead of the troublesome transformer. Is that not true? |
I agree, with IC is way more simple. With trafo(you would have only one), you have primary that is somehow driven by SG or what you are using, and 4 secondarys, each for one fet, but I would go here with NPN transistors, like Mje 13009, which Eva says that are very good, are very cheap and small, they will have less dissipation then high voltage fets, probably because of their Rsd(on), which is higher as component is cheaper, you sure won't pay 10€ or in other words a lot of money for single fet to have low ON resistance... |
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| luka |
| quote: | Originally posted by golam
I have got the information from Tauscher Co. of Germany which produce good quality cores. I have collected some of their etd/ecr cores from China and used for my inverters. I used them for making 250 watt capacity ips. Those information from Tauscher Co. may be for continuous duty and for using 2/4 hours for ips, I think more wattage can be produced as duty cycle is less.
I tried to make 600 watt with those core with 80 KHZ but it becomes very hot and I am reverted back to 250/300 wattage.
For safe use over 500 watt, one require to use ETD-44 core- according to the Company. |
Everybody said that I won't be able to get power that I wanted from my ETD44, even when Eva show, after that I did too, that you can get more from core then it was writen on internet. I NOT saying that that company gives wrong info, but you just have to try for yourself
From Eva: At 36Khz, 2KW from two E42/21/20
And this is not way bigger core then what you have, I think... |
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| luka |
| quote: | Originally posted by golam
For Tahmid,
I tried with transformer for full bridge and faced lot of problem as the gate driving signals through transformer is not as efficient as gate driving dedicated ics. You can try but if you ask me, I will advocate to use dedicated gate driving ics. |
You used fets, like I said use NPN, every PC psu works this way and it is great |
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| Tahmid |
| quote: |
Posted by Luka
I agree, with IC is way more simple. With trafo(you would have only one), you have primary that is somehow driven by SG or what you are using, and 4 secondarys, each for one fet, but I would go here with NPN transistors, like Mje 13009, which Eva says that are very good, are very cheap and small, they will have less dissipation then high voltage fets, probably because of their Rsd(on), which is higher as component is cheaper, you sure won't pay 10€ or in other words a lot of money for single fet to have low ON resistance... |
Why MJE13009 NPN transistor rather than MOSFET?
While using MJE13009, we must give a base current of 1Amp to be able to get an output of 5A. But while using MOSFET, for getting same output we require to provide only a few milliamps to the gate. So, it is easier to make electronic circuits with MOSFETs, rather than NPN transistors because 1A base current is hell lot of current for an electronic circuit. Instead of using current-mode transistor, it is preferable to use voltage-mode MOSFET, I think.
Moreover, we are getting ready-made totem pole gate drivers inside the SG3525, which costs US$0.5 only in Bangladesh. MOSFET is also very cheap here, only US$0.5-1.5, depending on power capability. |
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| luka |
Hi
Is it a problem for trafo to make 1A for Ib? it is way harder to have 12v for gate voltage then make 1A fot base, no problem with noise, to low voltage, oscilations and when current stops, colector/emitor current stops... If you would use MJE I think you should use trafo, or it will be harder to drive. And 1A is really nothing, coz 1A at say 1v of BE voltage is nothing... Fet needts at turn on more, say 12v^2/22R(gate resistor)= 6.5w... even if only at the beginning...it is not hard...you should try if you arent time limited too much, you can always go back to IR...+ it would be something fresh to see usage of gate trafo in designs on this forum. And because you have full bridge, where is best to use it, since you have so many fets, floating points...
You still will use SGs output, to drive trado directly... fets are cheap...which ones will you use/how much will they cost you if you do use them?
PS: only 0.5$ for SG? damn don't do this, I will buy them from there :D |
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| golam |
For luka,
Yes, NPN Transistors can be used but think about Base current. In an electronics circuit, if you get your required output with providing mA instead of providing some A current, which is preferable? I consider Mosfets. If anyone prefer Transistors, he can find out ESBT from ST Microelectronics, where he can utilize that Transistor with the same mA of current like Mosfets applying to the gate/base of ESBT(Emitter Switched Bipolar Transistor). |
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| golam |
| ESBT does not require gate driver. It is like all other normal transistors. |
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| areza |
for 50hz dc-ac inverter , there are cheap solution , no need to use those expensive ir2110 driver cost more then all 4 mosfet used in full bridge , and will explode with the mosfet on the event of a failure,
ir2110 is good (price to performance) for say >20khz hard switching application , and has limited gate driving current, |
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| luka |
Hi
All is relative, I don't mind 1A for base current. This is no down fall, what will you gain by using fets that as you say need only mA. Is it hard to creat 1A with trafo? trafos are way better when it comes to error, they don't explode or anything. Don't get me wrong I used IR too, it is just simple to understand and it works great, not much components around it. But with 50Hz freq., which is low for IR, you would need big C for upper gate drive.
To be short: what Areza said!
PS: you could make your own driver, like UCD has, it is IR but with discrete components |
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| areza |
| hi luka, i m agreed with u , i want to use trafo for both 50hz and 20khz , with variable duty cycle(say 0-100% again), is there any way to do it with trafo, thanks |
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| luka |
Hi
No, not for 100% for sure, if you put DC on primary trafo will in xx time have 0v on secondary, while it should have voltage.... so if you need 100% D.C., let say almost all the time on, very little off, trafos are not good. Why do you need 0 and 100%?
I mean do you really need from 0 to 100? or would be 5 to 95 ok? |
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| areza |
| hi luka, i want to build a class d amp with trafor for music , is there any way useing trafo , or some thing else like opto may be, i was looking all over the class d forum without any luck, but i m sure there is some way, |
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| Alexsch |
| In 2008 using a MJE13009 BJT instead of MOS is like giving up a BMW750 for a horse drawn cart. Even the very cost sensitive lamp ballast circuits are moving to MOS. Decent base drive of the BJT at >30KHz are a difficult circuit to design and it needs some tweaking to get it right. On MOS: give it 10V gate pulse, and add some 5ohm de-Qing resistor. |
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| luka |
| quote: | Originally posted by areza
hi luka, i want to build a class d amp with trafor for music , is there any way useing trafo , or some thing else like opto may be, i was looking all over the class d forum without any luck, but i m sure there is some way, |
Well I am not sure, if you would have low freq. for say sub amp, you may be able to use it, but for amp I would and I did use IR, it is just more simple, trafos are best in supply. And you don't need 0-100% duty cycle, you can use only 25-75%, and because of this use higher bus voltage so D.C. has to change less then with lower bus voltage to produce same output voltage |
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| luka |
Hi Alexsch
Why would you not compare them? I mena most can't get brand new fets, they aren't cheamp,... + people use what is proven to work great. Why would you force fets in say full bridge supply if you can get better performance with damn old components like MJE.
All I am saying fets are getting better, but shops still sell only 10 or more years old fets, coz they *work*...hell I would want new fets, but hell if they don't buy them, I can't, and I live in EU not say in africa in middle of nowhere and probably they get more stuff then I can:mad: |
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| Alexsch |
| You may use Digikey or Mouser. Use VISA or similar vay of payment. Relative to hobby electronics shops they may end up even cheaper.:xeye: I am not against BJT as a device, and willingly go for "quasi-bjt" (IGBT) if reason exist. They are very difficult to drive, those BJT's. Thats the real reason. And in order to have fast switching times you need baker-clamps or some very fancy BASE-Drive circuit. And baker-clamps increase conduction losses. On the other hand if you stick to even the old cheap IRF840 with Half-Bridge or Full-Bridge configuration, you may, by clever design do 1-1.5kW SMPS. Provided, you know what are you doing of course :cool: . I really don't know your situation. In Israel we can have IRF840 easily, i personally like the 20N50 types from Infineon/IR/ST. Yes, those are 20A 0.22ohm 500V units. (Except i do not value those "8.5A" or "20A" statements. Its all dependent on your heat removal abilities.) |
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| Alexsch |
"...say in africa in middle of nowhere "
A nice description of my Middle-East. Not very accurate, i would say.:D |
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| golam |
| quote: | Posted by areza
for 50hz dc-ac inverter , there are cheap solution , no need to use those expensive ir2110 driver cost more then all 4 mosfet used in full bridge , and will explode with the mosfet on the event of a failure,
ir2110 is good (price to performance) for say >20khz hard switching application , and has limited gate driving current, |
Using transformer for gate drive is not a cheap solution.If you add your problem while using transformer,cost will be more. At least I find while testing. Ir2110 costs same as mosfet in Bangladesh and so, I don't find it costlier.I don't understand why you should not use modern ready made gate driver ics for saving few pennies. Alexsch has properly pointed out and I do agree with him.
Ir 2110 is having 2A gate driving current which is 4 times greater than sg3525. I think this amount of current is enough for making an Inverter with a capacity of 5 KW. Are you thinking in the line of making inverter of 10 kw capacity? Then you are right. I am discussing regarding an inverter <= 500 watt capability. |
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| golam |
| quote: | Posted by luka
All is relative, I don't mind 1A for base current. This is no down fall, what will you gain by using fets that as you say need only mA. Is it hard to creat 1A with trafo? |
| quote: | Posted by luka
Why would you not compare them? I mena most can't get brand new fets, they aren't cheamp,... + people use what is proven to work great. Why would you force fets in say full bridge supply if you can get better performance with damn old components like MJE. |
Creating 1 Amp is not problem. Problem is using 1A in lieu of mA in the circuit. When every body is trying hard to make the circuit smaller by infusing less current, then what is the use of making bulky current eating transformers? I find it is beneficial in using mosfets.
Nobody is forcing anybody to accept anything. Logic is forwarded so that good sense can be applied. It is up to the individual to accept the better and modern ones instead of sticking to the past and continue to use old but inefficient products.
If you want to stick to use transistors, switch to ESBT which is more efficient and requires mA of current for gate/base drive. |
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| areza |
hi golam , since u asked why i m after transformer gate driver, cos i m designing a class d half bridge inverter for 50 hz sine wave , as its a half bridge so to produce 310 v ac pick , i need 620 v dc (+310 - 0 -310), now its lots of voltage to kill the whole driving stage if one of the igbt fails, and there is a very good possibility that they would explode on design phase , i dont want to change the whole control system every time mosfet or igbt fails, transformer will keep the voltage away from control stage and save my invest,
u r rite i m looking at 10kw, i already archive 1kw , without much problem, |
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| Tahmid |
Thank you Golam, Luka, Areza and everyone who helped.
I have just completed the step up section of my SMPS IPS. I rewound my transformer according to the details provided by Golam, have used IRF3205 as suggested by Areza and I thank Luka for his suggestions. I have used 30kHz oscillator with SG3525 and the step-up section has been tested successfully with converting 12v dc to 240v dc and 300W load. It is working perfectly and no significant heat is produced.
Now I am moving onto the Full Bridge circuit for making this 240v dc to 220v ac. I will attempt both gate driver and MOSFET as well as MJE13009. |
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| Tahmid |
I agree with what Alexsch said.
I have also checked out the ESBT and recommend all those who are using BJTs to move onto the ESBT. |
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| luka |
Hi Alexsch
Ah 840 are easy to get here, but they are old, no fancy new stuff from fairchild or similar. Irfp 450 or 460 or Irf 840 is not my idea of new, great transistors, more like basic, but all are available here... their performance is good until you need better :D |
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| luka |
| quote: | Originally posted by golam
Ir2110 costs same as mosfet in Bangladesh and so, I don't find it costlier. |
That is benefit of living in countery where everything is less expensive and lower tech (Please take no offense , I have nothing against that, just trying to point out, more money you have more you going to pay for stuff you buy) IR2110 here is in one store: 5,34 €, other one in my city: 3,0875€ if they have it, or they order it and you have to pay 50% more :(
| quote: | | bulky current eating transformers |
This trafos are very small, smaller then IR, you have them in PC supplys and don't say they are big and current demanding...no more then IR is |
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| Tahmid |
luka,
You can try IRFP460. It is good and is the one I intend to use for my Full Bridge circuit. |
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| luka |
| quote: | Originally posted by areza
hi golam , since u asked why i m after transformer gate driver, cos i m designing a class d half bridge inverter for 50 hz sine wave , as its a half bridge so to produce 310 v ac pick , i need 620 v dc (+310 - 0 -310), now its lots of voltage to kill the whole driving stage if one of the igbt fails, and there is a very good possibility that they would explode on design phase , i dont want to change the whole control system every time mosfet or igbt fails, transformer will keep the voltage away from control stage and save my invest,
u r rite i m looking at 10kw, i already archive 1kw , without much problem, |
I think you need not to worie, since you start small and go up from there, only when you know that everything is working ok you go for higher voltage... IR would be easy to start with, but you need to make it robust for such application, where gate trafos are probably indestructable +
you get insulation, which is great if you have control circuit on secondary side, you can sense voltages by simple voltage deviders, sense current, all that |
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| luka |
| quote: | Originally posted by Tahmid
luka,
You can try IRFP460. It is good and is the one I intend to use for my Full Bridge circuit. |
I like 450 more, cheaper, 2.8€ compared to 4€ for 460... And like 14A isn't enough :D even for half bridge |
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| golam |
| quote: | Posted by areza
hi golam , since u asked why i m after transformer gate driver, cos i m designing a class d half bridge inverter for 50 hz sine wave , as its a half bridge so to produce 310 v ac pick , i need 620 v dc (+310 - 0 -310), now its lots of voltage to kill the whole driving stage if one of the igbt fails, and there is a very good possibility that they would explode on design phase , i dont want to change the whole control system every time mosfet or igbt fails, transformer will keep the voltage away from control stage and save my invest,
u r rite i m looking at 10kw, i already archive 1kw , without much problem, |
hi areza,
thanks. I am very happy that you have made 1 KW inverter. I am happy. But sometimes your postings create some confusion. Sorry. I don't post here to show what I am doing or I can do. My aim is to help those like Tahmid who are at the preliminary stage and need our help for moving forward. I am actually giving him the tips what I have done few years before so that he/others can start from lower level.
I am engaged in smps and embedded system designing for Industrial Automation. I actually design smps with Pic Microcontroller- Pic 18f series ,not with discreet ics.
I produce micro controller based inverter for Butt Welding M/C, high frequency inverter for Induction Heating etc. Recently I have tested my Single Microcontroller based sine wave inverter -upto 1.5 kw for consumer purpose with ETD-49 core. Shortly I will market my sine wave inverter or I may sale my technology as discussion is going on with a renown Company.
I also will try to open a new thread here for making smps with Pic Microcontroller- not using discreet Ic only.
CLEARING DOUBTS REGARDING HALF- BRIDGE CONFIGURATON
Probably you are not clear about inverter configuration. Half Bridge does not require 620v(310-0-310) but only 310 volts as in half bridge configuration, full windings are used, not half windings like push-pull. So, you do not require center tapping and 620v (310-0-310v ) rather 310v in opposite phases. So, you require a mosfet like irfp460 which can handle 500v. If you don't understand what I said and stick to 620v, your mosfets always will blow away and your 1k inverter will not see the light of the day.
Luka said that we are in low tech country but all of us are not working with low tech. Certainly, some of us are talking big with shallow knowledge.
Again, if I hurt you regarding my posting, I am sorry. |
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| luka |
Hi
| quote: | | Luka said that we are in low tech country but all of us are not working with low tech |
I know it would come out like that, hope you know what I mean, hope no bad filling, I wouldn't want that. I would also try to help as much as I can to anybody that would need help.
Nice to hear someone is using uC to control, I must say if you know what to write for program it must be really "easy" to make it better and better. Hope you will show some pic of anything sometime |
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| areza |
hi golam , sorry to make u confuse, if u have a look on some application notes from some semiconductor manufacture and some power amp manufacture (crown, ir , st etc)
on there proprietary topology and general design then u will se what i m talking about, class d need split power supply, a single power supply with capacitor split bus would cause imbalance and catastrophic failure,
please make your self educated enough before u comment on some thing on this forum,
evidently you dont know what you are talking about power electronics and microcontroller, |
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| Tahmid |
areza,
You said class d requires split power supply, that is +310v and -310v with a common ground. This is actually 310v in two different phases, one positive, the other negative. 620v will be found if measured at -310v reference, not ground reference. Thus, I think that it is improper to call this 620v, but should be referred to as +/- 310v.
And, each MOSFET should be capable of at least 500v or more if possible, but 620v is not competely necessary, as each MOSFET will actually be tackling either +/-310v. 500v will suffice. |
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| areza |
| tahmid @ well to produce 220V AC RMS u need +/- 310V DC after rectification and compensation , semiconductor is not the problem , the IGBT i m gonn use is 600A 15A at 100 degree Celsius, |
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| golam |
Areza,
Actually you are correct. I know very less regarding Power Electronics and Microcontroller because still I am learning and could acquire very less till today. Still I am learning from Luka, Tahmid and all others and also from you and others. But could not get some, as their teaching is confusing. This is a vast field and I hope to learn till death. I will try to educate myself specially learning lessons from your postings before commenting in the forum. Thank you again for your valuable advice. |
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| Tahmid |
Areza,
Your question as well as answer is very confusing.
Now you have stated that it is +/- 310v whereas earlier you have referred to it as 620v and you said that you required MOSFET/IGBT capable of more than 620v. Please make your question and reply clearer and easier to understand. |
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| Tahmid |
Areza,
There is also a confusion/miscalculation regarding your 10kW inverter.
You mentioned that you are using 600v 15A IGBT.
You are using 310v across each IGBT and maximum amperege is 75% of the capacity (you should not use more than 75% of a semiconductor's capacity for safety purpose) that is ~12.5A. This stands at a maximum power capability of 310v X 12.5A = 3.875kVa. And even if you use maximum capability, 15A, you get 310V X 15A = 4.65 kVA.
How do you expect to achieve 10kW (not 10kVA) power from your configuration? There will also be some power losses through different components. So power capability gets even lower. How do you expect to achieve 10kW from this configuration? :bigeyes: :bigeyes:
Hope you will make it clear so that I can learn from you. |
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| areza |
| tahmid @ i m not questioning , i m just looking for batter topology and ideas, look for some appnote on class d then u will understand what I m trying to point out, I already have the required semiconductor and some of magnetics I need, the half bridge controller will se +/-310 v = 620 v , u got the point? |
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| areza |
| the igbt is rated 27 a @ 25 c, its for prototyping , when I get everything under control I will replace them with rated one, |
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| Tahmid |
Areza,
Actually I am not still clear regarding your configuration. Probably, I do not have adequate knowledge to fully understand what you mean. |
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| Tahmid |
Luka,
Actually I am not getting what Areza is trying to say.
Can you please make me understand what Areza wanted to mean? I want to know this clearly because I think it is a very important lesson for me. |
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| Tahmid |
| Suggestions for 220vdc to 220vac square wave conversion will be appreciated.:) |
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| Tahmid |
| quote: | Posted by areza
the igbt is rated 27 a @ 25 c, its for prototyping , when I get everything under control I will replace them with rated one, |
Should you not always consider current rating of an IGBT/MOSFET at 100/125 degree centigrade? |
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| areza |
| tahmid dont worry u will know if u really want to, its not easy as I said , there is lots of challenge , it’s a difficult task but not impossible if some one spend enough time and resource, |
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| Tahmid |
Golam,
Could you make me understand what Areza is trying to say? |
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| luka |
Hi
LOOOOOOOOOOL now you are loosing me :D
ok first if full-bridge, single 310v will be enough, next cooler the fets, transistors of anykind for that matter, can handle more current, so if 15A at 100C, then it will have more current at 25C without destruction, I think it was said 27A.
if you look at 27A x 310v that is 8.37kVA, but that is peak power, but that converter would be 4.2kVA, rms if you want...
I far as I know nobody said nothing about how powerful will be inverter, its not 1kw, not 5k, not 10k
He will tell us once he will know/or tell us...
Don't fight, lets all understand everything, so lets all try to Ask and Answer, ok?
PS areza: why don't you do FB?? I think you should |
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| Tahmid |
Luka,
I am going for square wave inverter. In square wave, RMS and peak voltage are the same. So, in the full bridge circuit, shouldn't I use approximately 220vdc to get 220vac out? Do I require 310vdc? If yes, why? |
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| areza |
| its all mixed up, cos of linguistic barrier and everyone talking there kind of things and everyons voice mixed up, makes everyone misunderstand to everyone else, i was talking about my current project and future one, it was 2 deferent project and some basic theory. |
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| luka |
| quote: | Originally posted by Tahmid
Luka,
I am going for square wave inverter. In square wave, RMS and peak voltage are the same. So, in the full bridge circuit, shouldn't I use approximately 220vdc to get 220vac out? Do I require 310vdc? If yes, why? |
Ah if you go for that way, you heed 220v, yes and not 310 |
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| luka |
| quote: | Originally posted by areza
its all mixed up, cos of linguistic barrier and everyone talking there kind of things and everyons voice mixed up, makes everyone misunderstand to everyone else, i was talking about my current project and future one, it was 2 deferent project and some basic theory. |
There will always be this, but not to worry,we will find common path...but for now try to stick to what you are doing now, not what you will, could you? So you will do HB, why not FB? |
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| Tahmid |
Luka,
Thank you for your clear and simple answer. You have cleared my doubts. |
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| luka |
Hi
No problem :), so how far along are you, anything to show yet? |
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| areza |
| i have no intention of overemphasize what i m doing or will do , some one just ask me about it so i replied, and all my post i was just answering things i asked for, may be some suggestion based on some real scenario, any way i don’t really want to argue with people and west all of our times , its just diying , so i m out of here, |
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| golam |
Tahmid
What is the progress? Could you make 220v DC to 220v AC through Full Bridge Circuits? Do you require a circuit? If any sort of help require, we are there to help you. I will try utmost to help you. While making circuit, please use low ESR Capacitors because these Capacitors are the real culprit- failure of them is one of the main cause of circuit failure in high frequency application. |
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| Tahmid |
Here is the full bridge circuit. Hope that it is correct and that you will notify me of any errors.
Parts:
C1,C2,C3,C4 - 0.1uF 50V
C5,C6 - 4.7uF 50V non-polar
R1,R2,R3,R4 - 22 ohm
R5,R6 - 220 ohm
D1,D2 - 5V Zener Diode
D3,D4 - UF4007
IC1,IC2 - IR2110
Q1,Q2,Q3,Q4 - IRFP460
Input is given to pins where IN is written. |
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| Alexsch |
1. If it is a square wave inverter, it is very simple indeed. Just make one 220Vdc rail and switch a Full-Bridge at 50Hz. By the way, you may also use simple opto-couplers for the upper FET's. More reliable and makes less damage, should the bridge fail.
2. If its a sine-wave converter, things get complex. There are several vays to go, 3 are very obvious:
A. Use a 20-50KHz class-D audio amplifier to create 24Vpp (from 12V battery) AC voltage. Use a simple iron trafo to rise that to 230Vrms. Nice, very safe way of doing things.
B. Use a sine-modulated Push-Pull or Bridge based PWM with HF (Ferrite) transformer to create a "rectified" sine waves with the correct amplitude. Use a synchronized low speed IGBT/MOSFET "inverting" bridge to transform the "rectified" full-wave sine to full-AC. Dont forget the antiparallel diodes on this slow bridge, that is, when using a IGBT's. A PIC18 uC can help you a lot, while going with PIC16F may be better, as it is so much simpler. Both PIC's can store a half-sine waveform in FLASH, creating an ANALOG sine reference for the PWM chips, or may themselves output a sine-modulated PWM. In second case, one have to know a bit on PID algorithms, otherwise he can expect a long and "interesting" (frustrating) time scratching his/her head in front of a black-burned pile of precious electronics, he just built.
And dont forget to add a discharger to the "rectified" wave, otherwise you get a very distorted sine on light loads.
C. Use an SMPS to do a +350V and a -350V rails, with a center tap. Use PWM modulation with optic drive to drive those IGBT's. Depending upon the PWM algorithm, you may need a 900V devices. But the sine wave will be better. The second algorithm may let you get away with 600V devices, but the sinewave will be more distorted on very complex loads.
Oh... and try to avoid those SG3525 controls when doing Push-Pull or a DC connected Full-Bridge. There is no way to insure correct flux balance in Voltage-Mode-Control. Watch it!
Question to Golam: what type of architecture an control you have used in PIC18F Inverter? What efficiency you could acheive? How long the project took? Did you used an on-chip PWM to make the sine? If yes, how many PWM bits were used? What THD did you get? What do you think is the real advantage for using a uC instead of cheap PWM chip? |
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| areza |
hi Alexsch , i like to know about the topology you mention above , say for instance which one you would adopt if you want to build one ,
i like to know few more things,
1 . i believe the class d with iron core , can be scaled to 350v full bridge to eliminate the iron core, i m on the rite path ?
2. what do you mean by “add a discharger to the "rectified" wave “ ?
3. which topology would allow open loop or less complex loop control/feedback ?
4. wanna know your opinion on “ one of the MIC topology “ named as “DIRECT DC-AC INVERTION “ outlined as , pwm modulated sine wave feed into a isolated DC/AC converter , the content is retrieved through a set of low pass filter,
thanks in advance for your time. |
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| golam |
Answer to Alexsch
My modalities for making sine wave inverter is conventional. First I made DC-DC Boost Circuit for converting 12/24/48 v dc to 310 v dc. Then I convert that into 220v pure sine wave through Hardware pwm through Pic Microcontroller and lastly demodulating the modulating frequencies(50 KHz) through LC Filter.
I also once made sine wave inverter with silicon core. Modalities were to apply the Modulating Pulse(6 KHz) and demodulate that frequency before the Transformer with LC Filter, so that Transformer see only 50 Hz and output also 50 Hz sine wave. I don't like Bulky Transformer and hence switched over to high frequency.
It took 1 year to develop the final one.
I used 18F1320 as it is having inbuilt mechanism known as ECCP. This Enhanced Pulse Width Modulation system is assigned 4 Pins for hardware PWM for Full Bridge Application. Yes I use this on chip pwm system. I developed a sine table, error correction table and feedback system to effectively carryout the instructions according to the table and ECCP Pins provide signal and corrected signal while it is running . This Pic can write /rewrite the program memory on the fly if proper program is written to do so. WDT rechecks the new rewritten table after each full cycle (20 mili second) and in case of extreme distortion, reset the controller.
Total pwm Bits are 256x4. for each full cycle- 20 mili second. Actual sine table is 256. The use is as follows:
256 bits from 0 to 255 from start to the peak for 1st quarter cycle, then 255 to 0 from peak to down- 1st half cycle complete. Next the same routine in the opposite phase to complete the next half cycle. So, 1 full cycle of 20 mili second is completed with only 256 bits actually.
With the help of ECCP, I turn on the 1 high side mosfet on and then provide pwm signal with 50 KHz to the lower one for half cycle and then turn off those 2 mosfets and turn on the other high side mosfet and provede pwm signal to the lower mosfet for next half cycle.You can not provide pwm signals to the upper mosfets. Rather they will be turned on for full half cycle alternatively and lower ones should be pwm-ed. The Cmos gate don't allow punch- throw, that is don't allow the upper and lower side mosfets of the same side to conduct simultaneously and prevents short circuit.
The efficiency is 89% and harmonic distortion is<7%.
I actually don't like to use discreet ics,if I can use micro controller. With Microcontroller you can do things which may require more than dozen discreet ics. You see, Pic 18F1320 is having internal 8 MHz oscillator, multichannel 10 Bit ADC, which can give you conversion result within 1.6 micro second, internal 2 Comparators with programmable internal voltage reference and you can toggle the output with program. 16 Bit Compare, 16 Bit Capture, Hardware PWM, single instruction cycle(with in 100 nano sec) add,subtract and multiplication capability, serial communication facility etc.etc. How many descreet ics require to ensure all this?
I use free MPLAB IDE of Microchip, PIc Microcontroller itseslf and the Programmer, made by me and I feel confident to do anything electronics. Any body, who does not know Microcontroller, it will be difficult for him to cope up with the trends of future electronics. This is the remark of the production in charge of a big Japanese electronics company-- right or wrong, I believe it.
With many many Thanks. |
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| golam |
Alexsch,
Do you require the sine table in detail to study?
If you require any help from my side, you are always welcome. We must help each other to develop our mental faculty. Fighting is easier, mutual co operation is not easier all the times.
Thanks. |
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| kaosad |
Sorry to hijack this thread.
What is the difference between having a transformer with small and large number of turns (but turn ratio the same)? |
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| Alexsch |
To areza:
"1 . i believe the class d with iron core , can be scaled to 350v full bridge to eliminate the iron core, i m on the rite path ?"
Yea, sure. Why not?
"2. what do you mean by “add a discharger to the "rectified" wave “ ?"
I am adding some schematics of what i have posted previously.
On your question about the discharger, look at the image lf_bridge.GIF. See C1+L1? You must have them both. The first stage here is a "simple" SMPS, except of course, that instead of a stable DC reference like the TL431 in "normal" regulators it gets a "rectified sine", which, of course this circuit will attempt to reproduce, multiplied by 1:N of the trafo. The second bridge merely inverse rectifies this waveform at 50Hz to get a full sinewave at the output.
Remember that the DC/DC-HF side of the converter is UNILATERAL, that is it cannot DRAW current FROM C1, only to charge it. It is up to the LOAD to discharge C1 to 0V at the start and the end of each half sine.
Now, if your LOAD is resistor, you have no troubles. But if your load is reactive/nonlinear, you need to have a reliable bleed to keep the capacitor C1 in the correct voltage.
The bleeder MOSFET is opened by the comparator each time C1 charges too high, keeping nice sinewave at the load.
"3. which topology would allow open loop or less complex loop control/feedback ?"
Open loop SINEWAVE inversion? To my opinion.... impossible! A nice feedback can be by a simple low power 50Hz trafo.
"4. wanna know your opinion on “ one of the MIC topology “ named as “DIRECT DC-AC INVERTION “ outlined as , pwm modulated sine wave feed into a isolated DC/AC converter , the content is retrieved through a set of low pass filter"
What do you refer MIC? For me its Microwave-Integrated-Circuit, which means mostly a chip&wire hybrid technology, not related to power electronics at all. If you refer to the circuit with C1, i may add that it is very nice as long as you wont wenture with it more than, say 500Wrms. The bleeder starts to be heavy after this. |
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| Alexsch |
Thank you for your help.
Back in 1996-7 i tried to make a 24VDC->230VAC inverter. I built it by using a PWM peripheral of 4MHz PIC16C72 modulated by 100 steps half sine and synchronized to the 50Hz mains by the software. The actual PWM was SG3524 with an AC coupled Full-Bridge of, 60V MOSFETs driven at 50KHz by 2*IR2110. The uC was used to supply a rectified half sines, RC filtered, and fed to an error-amp of this SG3525. It also commanded a 50Hz IRF840 bridge to invert the half sinewaves. I used 3C85 ETD44 or ETD49 (...don't remember) transformer with silicone-laminations inductor at the output.I partially got it working, but cancelled it all, after a while, by lack of my boss interest.
High efficiency power electronics was always one my favorite interests, because it is so complex and such a cruel and unforgiving challenge. But now, as the energy crisis is upon us, humans, we, the power electronics experts can do a lot for everyone. Leave alone Al-Jazeera false horror stories garbage. So now i am interested in inverters also from their "green" aspects.
And you actually made a working unit. So i am obviously curious about it!
I am a little confused about the uC issue. You say, that you made a 90 degrees portion of a sine by 256 points. Thats 0.35 degree resolutuion! But your actual PWM was 4 bits, thats 16 combinations. For a 310Vpp sinewave you have 19.375V steps. I am kinda confused about the very high phase resolution against so crude an amplitude resolution.
Is that what made your THD=7%?
Also 4 bit PWM times 50KHz is 16*50e3=800KHz not 8MHz as the chips clock...
Also WDT is merely a primitive prescaled timer that needs to reset every X mS. Failure to do so, makes the WDT to roll-over, resetting the uC by this. It cannot check if a FLSH table has been written... or i am missing something here?
Why do you need to rewrite the sine into flash? I am kinda thought, that self rewritable FLASH is very good for distant programming upgrade by internet or so...
The stated endurance of program FLASH is 100K times. Doing so 50 times per second gives 2000 seconds lifespan for the inverter. I am most probably missing here something.
Regarding my own stuff, i am interested in 3-phase space vector modulated Inverters an Rectifiers. Especially the algorithmic aspects that can be used by some uC, or, even better for me, an FPGA.
Also i still prefer the analog PWM chips like UCC2800 or UCC2808 series. They have an infinite resolution in terms of output voltage, and are very reliable.
I kinda cannot understand the very usage of voltage-mode-control like SG3525 in push-pull, like so many statements here...
And also i am very concerned about using a uC with PID algorithms, when, computing more than one output, it creates a huge REAL-TIME multiprocessing burden, and the bugs are just sitting there, between the lines of my very code, waiting for the opportunity to spoil my day.
In that, respectfully, me and you, as engineers, are different indeed in our views!
For me, uC management of SMPS on the other hand is a most welcome blessing. Using stuff like 16F884 with 13 10-bit A/D is very easy and saves a lot.
All the best.
Alex. |
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| Tahmid |
| quote: | posted by kaosad
What is the difference between having a transformer with small and large number of turns (but turn ratio the same)? |
The lower the number of turns, the higher the frequency has to be.
The higher the number of turns, the lower the frequency can be.
Otherwise there can be problems of core saturation, pulse imbalance and improper output.
Actually switched mode system was patronized by NASA for their requirement of small power supply for their spacecraft. That's why high frequency low number of turns high power SMPS has evolved. |
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| luka |
Hi
You see?? I didn't know that, never look into who needed it first and for what, I'm just glad they did |
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| golam |
Reply to Alexsch
Probably I could not make you understand regarding my sine wave modalities. I am attaching a diagram to make you understand.
Pic 16F884 is a beautiful piece of Microcontroller. It is of 40 pins. Due to programming difficulties like page changing etc. and specially writing data table like sine table in programme memory I have shifted to 18F series. As the program counter low(pcl) is of 8 bit it is very difficult to write more than 256 bytes of data in programme memory in 16F Series.
For small program, I use pic 12F675/683 of 8 pins, 16F884/888 for 14 pins, 18F1320 for 18 pins and 18F4550 of 40 pins. Earlier for 40 pins, I used pic 16F 877A.
There is problem in making sine wave inverter with 16F series. PCL is 8 bit, moreover max. frequency is 20 MHz, so your ADC result conversion is slower and lot of other difficulties which you will face while using. All these difficulties are not there in 18F series. So, using more than 14 pins, I switch to 18F series.
Sine table is not of 4 Bits. It is of 8 Bits. To offset 8 Bit PCL of 16F series, 8 bit-that is 256 combination in total is used different way 4 times in 4 quarters of a full cycle. Shown in the sketch attached in detail.
As I have used 16F Series Pic, I resorted to 8 Bit resolution for my sine wave table. Thats why efficiency is < than 90% and harmonic distortion is almost 7%. I just used my programs in 18F 1320 without modification.Now I am modifying my sine table to 10 Bits as I can use the whole program memory in 18F for storing Data. So, I will get 1024 combination and total sine table will be 1024x4. I have tested the 1st prototype with new program and found that efficiency can be as high as 94%. I require more 1 month to finalize the new one.
I have not used internal 8 MHz oscillator - rather I used 40 MHz pLL oscillator for getting my ADC result in 100nsx12 TAD=1.2 Micro sec.
Since I used 40 MHz oscillator, my instruction cycle is 100 nano sec. I used 50KHz freq for my inverter, so each pulse for inverter is taking 10 micro second for half cycle. After each PWM- ed pulse from ECCp, before providing next pulse, checking /rechecking/error calculation/modifying error count, Adc reading adjustment etc. required only 5 micro sec and doing every thing ready, just after each 10 micro sec, PWM signals are given by ECCP module to the gate of Mosfets through drivers if you use those at all and you are getting half of a cycle and with this operation ultimately you are archiving what you are intending for.
WDT in 18F series is different than 16F series and you can use it in 101 way if you use. Here, after each predefined time schedule, WDT goes to a Macro intended for it and according to that Macro some parameters will be ascertained and this checking requires only 2.6 micro second and it will not clash with normal calculation with in 10 micro sec time. WDT is not doing anything, every thing is done by Programmer but WDT is used as a tool for achieving his goal.
I tried to make you understand. I am still having lot of shortcomings regarding Power electronics and Microcontroller. I am trying utmost to overcome and suggestions from all members are welcome.
I think the sketch will help you to overcome some of your doubts. |
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| Alexsch |
4 Quadrants, not 4 bits. Yes i understand now. Your 89% efficiency, in my opinion is excellent, as you actually doung a DOUBLE-CONVERSION inverter, so the efficiency figures get multiplied. Regarding 7% distortion at 8 bit PWM resolution:
8 bits per quadrant give you 1.21V steps. I think it is very fine, and (without due expirience, i admit..) guess that it can be 1-3% at the most. Respectifully, i would suggest to look deeper into the switching algorithm or the control algorithm (did you used PI? PID?) for the explanation about those 7%.
Specifically, the 4-quadrant algorithm looks unidirectional to me. In that case it can easily correct for lack of voltage on the output final filter cap, but cannot withdraw excess charge, as i posted yesterday on a different type of inverter.
PIC18F indeed have a contiguous program memory, and in PIC16F one needs to observe his look-up tables carefully (...been there, seen that). I wanted to use PIC18F44J10, but got reluctant to learn 70+ assy instructions. Maybe in future, who knows.
All the best.
Alex. |
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| golam |
Alexsch
From 35 instructions in 16F, 77 instructions have been incorporated in 18F Series for the Compilers of High Level Languages like C . Most of the instructions are easy and simple to understand. Do not afraid of 77 Instructions. Electronics is a subject, which requires lot of hard work, patience and dedication. No short cut in Electronics. Instead of sticking to old and obsolete technology, adopt new and modern technology. You know better than me regarding this, as you are from a technologically advanced country. |
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| andig |
Hi everybody,
I stumled upon this thread and really did not read it in entirety. But I am seriously confused with the use of WDT in the PIC18F1320. Please help.
Golam could you please clarify how you setup the WDT for a 2.6 microsecond period and how to invoke a macro at timeout.
Regards
Sougata Das,
Andig Technologies,
Kolkata,
India. |
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| golam |
Dear Andig,
I am going to U.S.A. for 2 months for attending a course on Semi conductor devices. After coming back, discussion will be there.
Thanks. |
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| S.G. Mahbub |
Dear Golam,
Thanks for your information regarding sine wave inverter. I also use Pic18F1320 and trying to make a sine wave inverter with that Pic. I have understood your modalities but not clear regarding use of WDT. Did you want to mean that after a predetermined period, say- 20 mili sec, the WDT moves to a Macro and perform some checking task within 2.6 micro sec? Or what Saugata tried to mean that is correct?
Whatever your answer is, I am not clear regarding the use of WDT in Pic 18F1320 regarding making sine wave Inverter. If you get time in U.S.A., please try to make us clear. It will be of great help.
With Thanks and wishing your enjoyable journey to U.S.A. |
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| areza |
| S.G. Mahbub @ where do you get those PIC controller, if they are available in dhaka , how much they cost, how many types are available, where i can get them, can you give me some series numbers, thanks |
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| S.G. Mahbub |
For Areza,
If you are new in Pic Microcontroller, You should start with PIC 16F84A. This is available in Stadium market. You can try in Pacific Traders in Stadium(swimming pool) or New Mitsui in Moulana Bhasani outer stadium market. This will cost Tk. 110 to 140 each. You will get 8 pin Pic 12F 675 costs Tk. 55 to 65, 28 pin pic 16F873A costs TK.150 and 40 pin 16F877A costs Tk.250 to 300.
PIc 18F series are advanced level and I am in doubt about availability of those. I am collecting those from China. |
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| areza |
| hi Mahbub , thanks for the info, whats about other stuff , LCD, ADC, DAC, etc are they available , ?! |
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| S.G. Mahbub |
Dear Areza,
I normally collect my required parts from abroad as I collect those in bulk for my production house.
But everything is available in Dhaka if you are willing to spend money and put some effort to source those.
However, from which shop you collected your Ferrite Core for 1KW smps inverter? I require the address as I require those.
From local market, I could collect only ETD 39/ECR 40 cores, not other types as your one and each piece costs Tk.55. |
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| areza |
hi Mahbub , got those cores from one of my friend :D
really need to know how much those serial or parallel LCD cost, thanks |
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| luka |
Hi
I don't wanna say anything, but be on topic, use PM or email for off topic stuff
THANKS |
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| Tahmid |
Luka, my circuit using ir2110 is providing no output, so could you check to see if it is correct (the attachment provided earlier)?
Thank you for your help. |
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| S.G. Mahbub |
Areza,
Luka is correct. Please try to collect the information by physically visiting the market or E-Mail me. We should not use this forum any more for information which is personal or local in nature.
Thanks. |
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